Question

A bullet is fired from a gun. The force on the bullet is given by $ F=600-2\times {{10}^{5}}t, $ where F is in newton and t is in second. The force on the bullet becomes zero as soon as it leaves the barrel. What is the average impulse imparted to the bullet?

• A. 9Ns
• B. Zero
• C. 0.9 Ns
• D. 1.8 Ns

Answer 1

The Correct Option is C

$ F=600-2\times {{10}^{5}}t $ At $ t=0, $ $ F=600N $ As $ F=0, $ on leaving the barrel, $ \therefore $ $ 0=600-2\times {{10}^{5}}t $ This is the time spent by the bullet in the barrel. Average force $=\frac{600+0}{2}=300\text{ }N $ $ \therefore $ Average impulse imparted $=F\times t $ $=300\times 3\times {{10}^{-3}}=0.9Ns $